Answered by Shaykh Yūsuf Badāt
Is oral sex allowed in Islam? Can a woman or man kiss or suck each other’s private parts?
Jazāk Allāh Khayr/ Thank you for your question.
Oral sex refers to sexual contact between the mouth and the genitals or anus.
If oral sex (performed by a husband and wife) entails sexual fluids, discharge and impurities to be released, entered into the mouth and or swallowed (which is more than likely to occur), then it is prohibited and impermissible. This is the ruling that all mainstream Islamic jurists agree to, even in the case where one is unsure, however there is a likelihood of such fluids to be entered in to the mouth.
Islam is a religion that demands purity and cleanliness in all aspects of life.
If one engages in oral sex in such a way wherein there is no sexual fluids and impurities on the tongue or in the mouth, then it would be considered mukrūh (disliked). (See Fātāwā al Hindīyyah)
And Allāh Knows Best